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(No Model.) l

J. D. SMITH.. v DENTAL ENGINE. yNo. 598,295. Patented Feb. 1,1898.;

INVENTOR sattonzey l NWB@ STATES I PATENT FFlCEt JAMES D. SMITH,l OF CANANDAIGUA, NEW YORK, ASSIGNOR OF ONE-FOURTH TO JOHN S. ANDREWS, OF SAME PLACE.

DENTAL ENGINE.

SPECIFICATION forming part ef Lettere Patent No. 598,295, dated February 1, 189s.

Application met Aptuzt, 1897.

.To all whom it may concern:

Be it known that I, JAMES D. SMITH, a citi i zen of the United States of America, residing at Canandaigua, in the county of Ontario and State of New York, have invented certain new and useful Improvements in Dental Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make andA use the same, reference being had to. the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification. l

This invention relates to certain-new and useful improvements in dental engines, the object thereof being to provide adental engine with a driving-wheel the major portion of the weight of which is located at the periphery or rim thereof and to provide means for changing the point of contact of the driven wheel with the driving-wheel; also, to provide means for varying the contact or pressure of the driven wheel upon the driving-Wheel, a further object of the invention being to simplify the construction and reduce the cost of manufacture of this class of engines.

The invention consists in the novel means forsupporting the shaft upon which is mounted the driven wheel, so that theV position of the driven Wheel can be changed by moving a'bracket which is mounted on its support out of line with the shaft.

The invention further consists in the construction and combination of the parts, as will be hereinafter fully set forth, and specifically pointed out in the claims.

In the accompanying drawings, which illustrate my invention, Figure l is a side elevation, partly in section, showing a' dental engine embodying my improvements. Fig. 2 is a side elevation, partly in section, of the driven wheel and its shaft. Fig. 3 is a side elevation, partly in section, of the bracket, which is eccentrically mounted upon the standard; and Fig. 4 is a detail view.

A represents the driving-wheel, which may be made very much afterthe manner of a bicycle-wheel, as to the spokes, and it is provided with a heavy metallic rim ot and a solid rubber tire A. The hub of the drivin gWheel is suitably connected to a shaft ct', which has senti No. 633,740. (No motel.)

The standard, composed of the base C,the section B having verticallydisposed internally screw threaded sockets for connection with the sections E F, as clearly shown in Fig. `4. The upper end of the section E of the standard is reduced in size to form a shoulder and pivotpost, on which is pivotally seated a bracket D. To one end of the shaft ais attached a crank-arm b', which is suitably connected to a treadle mounted on the base or foot-piece of the standard.

The bracket D is connected to the tubular section E, `so as to be capable of a partial roe tary movement thereon, and it may be locked in a set Aposition by a thumb-screw d. The upper part ofthe bracketD has a shaft-beai1- ing, with bearings for rollers or balls, and the recess therein is internally threaded to receive the tubular section E', through which the driven shaft passes. The bearing D at the upperendof the bracket D forms a support for the driven shaft, and its lower end rests ina conical bearing d, consisting of a conical recess, adjacent to which are shoulders, and upon said shoulders rests a spring Which engages with' a Washer loosely mounted on the shaft Ff, said shaft having above the Washer a collar f, which is suitably attached to the shaft, Vsaid collar f being concave on its lower face to engage with balls f', which not only impinge against the collar and washer, but also against the side walls of the recess in the bracket.

The shaft F has mounted thereon a driven wheel Gr, the lower face of which is provided with two or more rubber rings or bands g g', which are adapted toengage with the perimeter of the driving-wheel. The wheel G is made of very light material, and upon the shaft, above the wheel, is a coiled spring H, one end bearing upon the upper surface of the wheel, while the other engages a coll-ar IOO or thumb nut h, which can be turned or adjusted upon the shaft, the turning of the nut tightening or loosening the spring, the nut engaging With the under side of the upper bearing.

The lowerend of the shaft F is supported by the spring d2, Which is of sufcient strengthV to sustain 4the weight of the shaft and the driven Wheel, the adjustment of the spring H governing the pressure of the Wheel G upon the driving-Wheel.

It Will be particularly noted that bearings for the shaft F are eccentric to the pivotpost carried by the tube E, so that by turning the bracket the position of the driven v Wheel With relation to the driving-Wheel Will be changed, such construction `providing-for a changeable speed, Which can be quickly effected. I consider this a very desirable feature of my improvement, asl in practice an operatorv soon acquires a regular pedalingvor treadle movement, and therefore the driving- Wheel will rotate uniformly, and when it is desired to have a low rate of speed the bracket is turned so as'to bring the periphery or outer ring of the driven wheelin engagement with' the rim of the driving-Wheel, and when a high rate of speed isr desired the bracket D is turned, so that. the inner band or ring will engage With the Wheel. v

To the upper end of the vertical shaftF is attached a iieXible shaft, the other end engaging With asuitable instrument or tool or the handpiece thereof. This iiexible shaft,y which is of the usual type, is reinforced by a suitable coiled spring or Wire.

The standard of a dental orA other engine of the same type can be cheaply constructed and readily taken apart for transportation and provides an effective means for changing the speed at which the tool is driven. The

spring support-ing the ball-cup of the driven shaft is vof such strength that it will support the Weight of the shaft and parts carried thereby, and the pressure of the driven Wheel throw the balance or driving Wheel to one side, which causes unnecessary friction and an uneven Wearing of the parts,and suchl construction does not provide for a changeof speed by simply moving the bracket upon'its supportingstandard. With vmy improved construction the driving-Wheel is provided Witha stub-shaft and ball-bearings, and the pressure is direct on the periphery or perimeter of the driving-Wheel.

I claiml. The combination in a dental engine, of

a standard-support and driving-Wheel supported thereby,l of a bracket mounted on the standard-support, a shaft mounted in bearings in said bracket eccentric to the bracketsupport, a Wheel mounted on the shaft carythe bracket, and ahorizonta'l Wheelmounted` on said shaft, substantially as shown'and for the purpose set forth.

y 3. The combination in adental engine, ofv a standard-support'having a. horizontal bearing, a shaft j ournaled in said bearing, a'Wheel ,mounted on the-shaft, a bracket carried by the standard-support, said bracket having 'gbearingsya vertical shaft journaled in the bearings of theV bracket, a Wheelcarriedzby 4the vertical shaft, a fixed collar onjthe shaft 4below the wheel, a spring-supported disk positioned inv the lower shaftbearing' of the bracket, and balls Whichengage with a fixed collar and disk, substantiallyy as shown and for the purpose set forth;

4. In-a dental engine, astandard-support, a, horizontal shaft journaled thereinand a driving-Wheel-mounted on saidshaftin combination Witha bracket'carried'by the standard-support and movably connected thereto, a verticalvshaft journaled in the bracket, a driven Wheel* mounted on the vertical-shaft above the driving-Wheel, aspring-support for the vertical shaft-in the lower journal-bearing of theA bracket and a spring located on the shaft to act against the first-mentioned spring to force the driven Wheel in contact' zwith the driving-Wheel and means for adjustling the latter spring, lsubstantiallyl as shown. t 5. As an improved article of manufacture ja supporting-frame for a dental'engine ycomp'rising ,a base provided centrally with an upWardly-projectin g portion having internal threads, a tubular section for engagement therewith, a hollow forging presentinghorizontal journal-bearings and vertical sockets, a section for engagementwith` the forging, said section having a pivot-postiand a bracket having asocket fork engagement with the pivot-post, the support and bracket carried thereby providing supporting means for the movableV or operativey parts of the engine, substantially as shown.

6. In a dental engine the combinationwith a standard-support and driving gear constructed substantially as shown, of a bracket pivoted upon the standard-support and having journals which are eccentric with the IOO IIO

pivotal point of connection of the bracket substantiallyas shown and for the purpose with the supporting-standard, and a Vertical set forth. 1o shaft mounted in said journals, aWheel hav- In testimony whereof I aflix my signature ing bands or rings for engagement with the in presence of two Witnesses.

Wheel of the drivin g-gear and means for adp l JAMES D. SMITH. justing the bracket upon its support to effect NVitnesses:

an engagement of eitherone of the bands or HERBERT G. FITCH,

rings with the perimeter of the driving-wheel, HARRY I. DNTON. 

